# C program to find given number is prime or not

Levels of difficulty: / perform operation:

# Program 1

```#include<stdio.h>

int main(){

int num,i,count=0;
printf("Enter a number: ");
scanf("%d",&num);
for(i=2;i<=num/2;i++){
if(num%i==0){
count++;
break;
}
}
if(count==0 && num!= 1)
printf("%d is a prime number",num);
else
printf("%d is not a prime number",num);
return 0;
}
```

# Result

```Enter a number: 5
5 is a prime number
```

# Program 2

```#include<stdio.h>

int main(){
int num,i,count;

for(num = 1;num<=100;num++){
count = 0;

for(i=2;i<=num/2;i++){
if(num%i==0){
count++;
break;
}
}

if(count==0 && num!= 1)
printf("%d ",num);
}

return 0;
}
```

# Result

```2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97
```

# Program 3

```#include<stdio.h>

int main(){

int num,i,count,n;
printf("Enter max range: ");
scanf("%d",&n);

for(num = 1;num<=n;num++){

count = 0;

for(i=2;i<=num/2;i++){
if(num%i==0){
count++;
break;
}
}

if(count==0 && num!= 1)
printf("%d ",num);
}

return 0;
}
```

# Result

```Enter max range: 50
2 3 5 7 11 13 17 19 23 29 31 37 41 43 47
```

# Program 4

```#include<stdio.h>

int main(){

int num,i,count,min,max;

printf("Enter min range: ");
scanf("%d",&min);

printf("Enter max range: ");
scanf("%d",&max);

num = min;
while(num<=max){

count = 0;
i=2;

while(i<=num/2){
if(num%i==0){
count++;
break;
}
i++;
}

if(count==0 && num!= 1)
printf("%d ",num);

num++;
}

return 0;
}
```

# Result

```Enter min range: 50
Enter max range: 100
53 59 61 67 71 73 79 83 89 97
```

# Program 5

```#include<stdio.h>

int main(){

int num,i,count,min,max;

printf("Enter min range: ");
scanf("%d",&min);

printf("Enter max range: ");
scanf("%d",&max);

for(num = min;num<=max;num++){

count = 0;

for(i=2;i<=num/2;i++){
if(num%i==0){
count++;
break;
}
}

if(count==0 && num!= 1)
printf("%d ",num);
}

return 0;
}
```

# Result

```Enter min range: 10
Enter max range: 50
11 13 17 19 23 29 31 37 41 43 47
```

# Program 6

```#include<stdio.h>

int main(){

int num,i,count,sum=0;

for(num = 1;num<=100;num++){

count = 0;

for(i=2;i<=num/2;i++){
if(num%i==0){
count++;
break;
}
}

if(count==0 && num!= 1)
sum = sum + num;
}

printf("Sum of prime numbers is: %d ",sum);

return 0;
}
```

# Result

```Sum of prime numbers is: 1060
```

# Program 7

```#include<stdio.h>

int main(){

int num,i,count,min,max,sum=0;

printf("Enter min range: ");
scanf("%d",&min);

printf("Enter max range: ");
scanf("%d",&max);

for(num = min;num<=max;num++){

count = 0;

for(i=2;i<=num/2;i++){
if(num%i==0){
count++;
break;
}
}

if(count==0 && num!= 1)
sum = sum + num;
}

printf("Sum of prime numbers is: %d ",sum);

return 0;
}
```

# Result

```Enter min range: 50
Enter max range: 100
Sum of prime numbers is: 732
```