1. Celsius to Fahrenheit

2. Fahrenheit to Celsius

#include <stdio.h>

void conversionC(){
    int celsius;
    printf("Type the degree Celsius (°C) you want to convert: ");
    scanf("%d", &celsius);
    printf("It is in %d°F\\n", celsius*9/5+32 );
    
    
}

void conversionf(){
    int fahrenheit;
    printf("Type the degree Fahrenheit (°F) you want to convert: ");
    scanf("%d", &fahrenheit);
    printf("It is in %d°C\\n", fahrenheit-32*9/5);
}

int main (){
    int userInput;
    printf("What unit conversion are you looking for?\\n");
    printf("1: Celsius -> Fahrenheit\\n");
    printf("2: Fahrenheit -> Celsius\\n");
    scanf("%d", &userInput);
    
    switch (userInput) {
        case 1:
            conversionC();
            break;
            
        case 2:
            conversionf();
            break;
            
        default:
            printf("You didn't choose anything from above\\n");
            break;
    }
    

    
    
}

Output: