C Programming Code Examples C > For Loops and While Loops Code Examples convert Decimal to Hexadecimal number system convert Decimal to Hexadecimal number system Write a C program to input decimal number from user and convert to Hexadecimal number system. How to convert Decimal to Hexadecimal number system in C programming. Decimal number system Decimal number system is a base 10 number system. Decimal number system uses 10 symbols to represent all number i.e. 0123456789 Hexadecimal number system Hexadecimal number system is a base 16 number system. Hexadecimal number system uses 16 symbols to represent all numbers i.e. 0123456789ABCDEF Algorithm to convert decimal to hexadecimal number system Algorithm Conversion from Decimal to Hexadecimal begin: read (decimal); hex = NULL; rem = 0; HEXVALUES[] = 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F; While(decimal != 0) begin: rem = decimal % 16; hex = hex + HEXVALUES[rem]; decimal = decimal / 16; end; Reverse(hex); print('Hexadecimal = ' hex); end; #include <stdio.h> #include <string.h> int main() { char HEXVALUE[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'}; long long decimal, tempDecimal; char hex[65]; int index, rem; /* Input decimal number from user */ printf("Enter any decimal number: "); scanf("%lld", &decimal); tempDecimal = decimal; index = 0; /* Decimal to hexadecimal conversion */ while(tempDecimal !=0) { rem = tempDecimal % 16; hex[index] = HEXVALUE[rem]; tempDecimal /= 16; index++; } hex[index] = '\0'; strrev(hex); printf("\nDecimal number = %lld\n", decimal); printf("Hexadecimal number = %s", hex); return 0; }