# How to set page title font size in R?

How to set page title font size is not clear in R's documentation. It can take a lot of time to figure out how to set font size. The following code shows how to change font size.

```# create a simple data frame
a <- c(1,2,3,4,5)
b <- c(1,2,3,4,4)
df <-data.frame(a,b)

# set up generated file name and page size.
pdf("plot.pdf", width=8,height=11)

# set number of diagrams on one page
par(mfrow=c(2,2),mar=c(4,4,0.5,0.5), oma=c(1.5,2,1,1))

# plot 3 lines
plot(df\$a,df\$b, type="l")
plot(df\$a,df\$b, type="l")
plot(df\$a,df\$b, type="l")

# add a title for the page
mtext("Three Diagrams in One Page", outer=TRUE,  cex=1, line=-0.5)

dev.off()
```

The font size of title can be configured by using the `cex` parameter of the `mtext()` method.

`cex` parameter controls the font size. The default value is 1. See the documentation for more details.

Category >> R
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```<pre><code>
String foo = "bar";
</code></pre>
```
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