 # C Program to Find First Digit Of a Number

C program to find first digit of a number; Through this tutorial, we will learn how to find first digit of a number in c program using log() & pow() , while loop and functions.

## C Program to Find First Digit Of a Number

• C Program to Find First Digit Of a Number using Log10() and pow()
• C Program to Find First Digit Of a Number using While Loop
• C Program to Find First Digit Of a Number using Function

### C Program to Find First Digit Of a Number using Log10() and pow()

```/* C Program to Find First Digit Of a Number */

#include <stdio.h>
#include <math.h>

int main()
{
int Number, FirstDigit, Count;

printf("\n Please Enter any Number that you wish  : ");
scanf("%d", & Number);

Count = log10(Number);

FirstDigit = Number / pow(10, Count);

printf(" \n The First Digit of a Given Number %d =  %d", Number, FirstDigit);

return 0;
}
```

The output of the above c program; as follows:

```Please Enter any Number that you wish  : 123
The First Digit of a Given Number 123 =  1```

### C Program to Find First Digit Of a Number using While Loop

```/* C Program to Find First Digit Of a Number */

#include <stdio.h>

int main()
{
int Number, FirstDigit;

printf("\n Please Enter any Number that you wish  : ");
scanf("%d", & Number);

FirstDigit = Number;

while(FirstDigit >= 10)
{
FirstDigit = FirstDigit / 10;
}

printf(" \n The First Digit of a Given Number %d =  %d", Number, FirstDigit);

return 0;
}
```

The output of the above c program; as follows:

```Please Enter any Number that you wish  : 2365
The First Digit of a Given Number 2365 =  2```

### C Program to Find First Digit Of a Number using Function

```#include <stdio.h>
#include <math.h>

int First_Digit(int num);

int main()
{
int Number, FirstDigit;

printf("\n Please Enter any Number that you wish  : ");
scanf("%d", & Number);

FirstDigit = First_Digit(Number);

printf(" \n The First Digit of a Given Number %d =  %d", Number, FirstDigit);

return 0;
}

int First_Digit(int num)
{
while(num >= 10)
{
num = num / 10;
}
return num;
}
```

The output of the above c program; as follows:

```Please Enter any Number that you wish  : 7895
The First Digit of a Given Number 7895 =  7```

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