Table of Contents
Programming Practices for If-Else
1. C program to find the greatest number among three numbers :
#include <stdio.h> int main(void) { int a, b, c; printf(" Enter the number1 = "); scanf("%d", &a); printf("\n Enter the number2 = "); scanf("%d", &b); printf("\n Enter the number3 = "); scanf("%d", &c); if (a > b) { if (a > c) { printf("\n Greatest number = %d \n",a); } else { printf("\n Greatest number = %d \n",c); } } else if (b > c) { printf("\n Greatest number = %d \n",b); } else { printf("\n Greatest number = %d \n",c); } return 0; }
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2.C program to find out whether a given year is a leap year or not :
#include <stdio.h> int IsLeapYear(int year) { // Function to check leap year. if (year % 4 != 0) return 0; if (year % 100 != 0) return 1; return (year % 400) == 0; } int main() { unsigned int uiYear=0; printf("Enter the year:"); scanf("%u",&uiYear); (IsLeapYear(uiYear)? printf("Leap Year."): printf("Not Leap Year.")); return 0; }
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3.C program to convert temperature from Fahrenheit to Celsius and Celsius to Fahrenheit :
The basic formula to convert Fahrenheit and Celsius to each other.
Celsius to Fahrenheit: (°C × 9/5) + 32 = °F
Fahrenheit to Celsius: (°F − 32) x 5/9 = °C
#include <stdio.h> int main() { float fh,cl; char ch; printf("\n\n Press c to convert temperature from Fahrenheit to Celsius."); printf("\n\n Press f to convert temperature from Celsius to Fahrenheit."); printf("\n\n Enter your choice (c, f): "); scanf("%c",&ch); if((ch =='c') ||(ch =='C')) { printf("\n\nEnter temperature in Fahrenheit: "); scanf("%f",&fh); cl= (fh - 32) / 1.8; printf("\n\nTemperature in Celsius: %.2f\n\n",cl); } else if((ch =='f') ||(ch =='F')) { printf("\n\nEnter temperature in Celsius: "); scanf("%f",&cl); fh= (cl*1.8)+32; printf("\n\nTemperature in Fahrenheit: %.2f\n\n",fh); } else { printf("\n\nInvalid Choice !!!\n\n"); } return 0; }
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4. C program to check sign of a given number:
The MSB bit of a number defines their sign. If the MSB bit is set, the number will be negative.
#include <stdio.h> int main() { int sign = 0; int data = 0; printf("\n\n Enter the number = "); scanf("%d",&data); //Get the number sign = (data > 0) - (data < 0); // check the sign of the number if(sign == 1) { printf("\n\n Enter number is a positve number\n"); } else if(sign == -1) { printf("\n\n Enter number is a negative number\n"); } else { printf("\n\n Enter number is zero\n"); } return 0; }
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5.C program to check whether triangle is equilateral, scalene or isosceles:
Before writing the program, we should know the properties of isosceles, equilateral and scalene triangles.
Isosceles triangle: In geometry, an isosceles triangle is a triangle that has two sides of equal length.
Equilateral triangle: In geometry, an equilateral triangle is a triangle in which all three sides are equal.
Scalene triangle: A scalene triangle is a triangle that has three unequal sides.
#include <stdio.h> int main(void) { int triSide1, triSide2, triSide3; /* Get sides of a triangle from the user */ printf("\n Enter first side of triangle: = "); scanf("%d", &triSide1); printf("\n Enter second side of triangle: = "); scanf("%d",&triSide2); printf("\n Enter third side of triangle: = "); scanf("%d",&triSide3); if((triSide1==triSide2) && (triSide2==triSide3)) { /* If all sides are equal, then Equilateral triangle*/ printf("\n Equilateral triangle.\n\n"); } else if((triSide1==triSide2) || (triSide1==triSide3) || (triSide2==triSide3)) { /* If two sides are equal, then Isosceles triangle*/ printf("\n Isosceles triangle.\n\n"); } else { /* If none sides are equal, then Scalene triangle*/ printf("\n Scalene triangle.\n\n"); } return 0; }
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6. C program to enter week number and print day of week:
#include <stdio.h> int main() { /* Declare constant name of weeks */ const char * WEEKS[] = { "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"}; int week; /* Input week number from user */ printf("Enter week number (1-7): "); scanf("%d", &week); if(week > 0 && week < 8) { /* Print week name using array index */ printf("%s", WEEKS[week-1]); } else { printf("Invalid input! Please enter week number between 1-7."); } return 0; }
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7.C program to check whether the triangle is valid or not if sides are given:
#include <stdio.h> int main(void) { int a, b, c, sum; //variable to store angles // Get three sides of triangle from the user printf("\n Enter 1 side of triangle: = "); scanf("%d", &a); printf("\n Enter 2 side of triangle: = "); scanf("%d", &b); printf("\n Enter 3 side of triangle: = "); scanf("%d", &c); //check validity of triangle if((a + b > c) && (a + c > b) && (b + c > a)) { printf("\n Valid triangle.\n\n"); } else { printf("\n Not valid triangle.\n\n"); } return 0; }
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8.C program to enter student marks and find percentage and grade:
A college has the following rules for grading system:
1. Below 25 – F
2. 25 to 45 – E
3. 45 to 50 – D
4. 50 to 60 – C
5. 60 to 80 – B
6. Above 80 – A
Ask the user to enter mark of 5 subjects and print the corresponding grade.
#include <stdio.h> int main(void) { float subMark[5]= {0}; float per = 0.0; int i = 0; float sum = 0.0; /* Get subject Marks from user */ for(i=0 ; i <5; i++) { printf("\n Enter subject %d marks: ",i); scanf("%f",&subMark[i]); //check validty of marks if(subMark[i]> 100) { printf("\n Enter valid number ! \n"); i--; } else sum += subMark[i]; } /* total marks */ printf("\n total marks = %f\n", sum); /* Calculate percentage */ per = (sum / 500.0)*100; printf("\n Percentage = %.2f\n", per); /*Grade according to the percentage */ if(per >= 80) { printf("\n Grade A"); } else if(per >= 60) { printf("\n Grade B"); } else if(per >= 50) { printf("Grade C"); } else if(per >= 45) { printf("\n Grade D"); } else if(per >= 25) { printf("\n Grade E"); } else { printf("\n Grade F"); } return 0; }
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9.Write a C program to input basic salary of an employee and calculate gross salary according to given conditions.
Basic Salary <= 10000 : HRA = 20%, DA = 80%
Basic Salary is between 10001 to 20000 : HRA = 25%, DA = 90%
Basic Salary >= 20001 : HRA = 30%, DA = 95%
#include <stdio.h> int main() { float basic, gross, da, hra; /* Input basic salary of employee */ printf("Enter basic salary of an employee: "); scanf("%f", &basic); /* Calculate D.A and H.R.A according to specified conditions */ if(basic <= 10000) { da = basic * 0.8; hra = basic * 0.2; } else if(basic <= 20000) { da = basic * 0.9; hra = basic * 0.25; } else { da = basic * 0.95; hra = basic * 0.3; } /* Calculate gross salary */ gross = basic + hra + da; printf("GROSS SALARY OF EMPLOYEE = %.2f", gross); return 0; }